How to slice a disc, and yet keep the pieces locked in together?
Start blender and delete the default cube.

Press Num Pad 7 for top view. Your scene should look like this:



Now press Shift+A and select Mesh ‣ Single Vert ‣ Add Single Vert



Now press Tab to enter edit mode. Press E then Y then 1 to extrude the vertex up on the "y" axis.



Now set Pivot Point to 3d Cursor.



Now press A until both your vertices are selected, then Alt+R to spin your mesh, and finally F6 to bring up the operator settings. Copy the values below (22 steps and 360 degree angle).



Now press A until until all vertices are selected, then go to Tool Shelf ‣ Tools ‣ Mesh Tools ‣ Remove: and click Remove Doubles.



Press Ctrl+Tab and select "Face"



Now select a face and press Y to separate.



Do that for all the faces and you are done.



I hope this helps you.